Electromyographic activity in paraspinal musculature in patients with idiopathic scoliosis before and after Harrington instrumentation
Donovan, W.H.; Dwyer, A.P.; Bedbrook, G.M.
Archives of Physical Medicine and Rehabilitation 61(9): 413-417
1980
ISSN/ISBN: 0003-9993 PMID: 7416931 Document Number: 167356
Ten patients with idiopathic scoliosis underwent electromyographic (emg) examination before and after Harrington instrumentation and fusion. Each patient had a normal emg preoperatively. At 3 weeks all 10 demonstrated spontaneous activity consistent with denervation, and voluntary activity was absent or markedly reduced. By 3 months and in some cases 6 months, denervation was significantly reduced or absent; voluntary activity had also reappeared and in most cases was equal to preoperative intensity. This rapid reversal of denervation after surgery within the paraspinal muscles in a young female population with no underlying disease suggests that interpretation of any postoperative emg should include considerations such as the time since surgery, the age of the patient, and the extent of preoperative pathology. No evidence was gained from this study that extensive posterior spinal surgery itself interfered significantly with paraspinal muscle function after 3 to 6 months.